External guide from fiber-reinforced plastic for use in a pneumatic spring system

ABSTRACT

The invention relates to a pneumatic spring system, comprising at least the following components, namely air-spring bellows, an air-spring cover, an air-spring piston and an external guide. The inventive pneumatic spring system is characterized in that the external guide consists of a plastic material with a solid support embedded therein.

DESCRIPTION

[0001] The invention relates to a pneumatic spring system as defined inthe introductory part of patent claim 1. Pneumatic spring systems ofsaid type are primarily employed in motor vehicle technology.

[0002] A pneumatic spring system of this type comprised of a pneumaticspring cover, a pneumatic spring piston and a pneumatic spring bellowswith an additional external guide is described, for example in thepublished patent documents DE-A-36 43 073 and DE-A-100 01 018. If needbe, the pneumatic spring system may be provided with a vibration damper(shock absorber) and/or a protective sleeve as well, whereby referenceis made in this regard to published patent document DE-A 197 53 637.

[0003] The pneumatic spring bellows is provided with an embeddedreinforcement in most cases, notably in the form of an axial bellows(DE-A-36 43 073; FIG. 1) or in the form of a bellows with a crossedlayer structure (DE-A-29 04 522; FIG. 2). With an axial bellows with itsaxially extending fiber reinforcements, it is necessary to equip thepneumatic spring bellows with an external guide. The external guide hasbeen made until now of a metallic material, in particular of an aluminumalloy.

[0004] Now, the problem of the invention is to provide at favorable costan alternative to the external guides known heretofore, notably withreduction of the weight at the same time.

[0005] Said problem is solved according to the characterizing part ofclaim 1 in that the external guide is made of plastic comprising anembedded reinforcement.

[0006] Useful further developments of the invention are specified inclaims 2 to 8.

[0007] The invention is described in the following in greater detailwith the help of exemplified embodiments and by reference to schematicdrawings, in which:

[0008]FIG. 1 shows a pneumatic spring system with an external guide.

[0009]FIG. 2 shows the cross section through an external guide.

[0010]FIG. 3 shows a fabric comprising a warp-and-weft structure; and

[0011]FIG. 4 shows a fabric with a crossed structure.

[0012]FIG. 1 shows a pneumatic spring system 1, whereby the pneumaticspring bellows 2 made of elastomeric material encloses an air chamber 3with an elastic volume. The pneumatic spring bellows is provided in thisconnection with an embedded reinforcement in most cases, in particularin the form of an axial bellows.

[0013] The pneumatic spring cover 4, which usually has the shape of apot, and which, furthermore, frequently serves as the pressurecontainer, comprises a first fastening area 5 on which the one end ofthe pneumatic spring bellows 2 is secured by means of a clamping ring 6.

[0014] The pneumatic spring piston 7, as a tubular structural component,comprises a face area 8 that is arranged opposing the pneumatic springcover 4. Said face area is laterally adjoined by the second fasteningarea 9 on which the other end of the pneumatic spring bellows 2 issecured. Said end of the bellows is fastened there by clamping by meansof a clamping ring 10 as well, whereby the end of the bellows is beadedaround the clamping ring. Said fastening area is provided with anundercut in most cases, forming a shoulder. Furthermore, as thepneumatic spring bellows 2 is compressed, a loop 12 is produced which iscapable of rolling off on the roll-off surface 11 of the pneumaticspring piston.

[0015] The external guide 13, which is secured on the pneumatic springcover and/or a structural component fixed on the body of the vehicle,and/or the pneumatic spring bellows (reference is made in this regard,for example to published patent document DE-U-298 23 508) substantiallyencloses the entire range of the pneumatic spring bellows 2.

[0016] Now, FIG. 2 shows the tubular external guide 13 made of a plasticwith high impact strength, which is preferably based on a polyamide orpolyester. The plastic is provided with an embedded reinforcement 14.Said reinforcement consists of fibers, in particular glass fibers, whichcan be mixed into the plastic. A fabric construction is possible as wellespecially provided with a reinforcement in the form of one layer,whereby two variations are introduced in the following.

[0017] According to FIG. 3, the fabric 5 is present in the form of awarp-and-weft structure, whereby the warp direction “A” is the axialdirection and the weft direction “B” is the peripheral direction(direction of arrow) of the external guide 13.

[0018] According to FIG. 4, the fabric 16 has a crossed structure.

[0019] Preferably glass fibers are used as base material for the fabrics15 and 16.

[0020] The external guide made of plastic with the reinforcementsincorporated therein leads to a reduction of the wall thickness and thusto a reduction of the weight.

List of Reference Numerals

[0021]1 Pneumatic spring system

[0022]2 Pneumatic spring bellows

[0023]3 Air chamber

[0024]4 Pneumatic spring cover (pneumatic spring pot; pressurecontainer)

[0025]5 First fastening area

[0026]6 Clamping ring

[0027]7 Pneumatic spring piston (roll-off piston, immersing piston)

[0028]8 Face area

[0029]9 Second fastening area

[0030]10 Clamping ring

[0031]11 Roll-off surface

[0032]12 Loop (rolling fold)

[0033]13 External guide

[0034]14 Reinforcement

[0035]15 Fabric with warp-weft structure with warp direction A and weftdirection B

[0036]16 Fabric with crossed structure

1. A pneumatic spring system (1) at least comprising the followingcomponents: A pneumatic spring bellows (2) made of elastomeric materialenclosing an air chamber (3) with an elastic volume, whereby thepneumatic spring bellows is provided with a reinforcement in most cases,in particular in the form of axially extending fiber reinforcements. Apneumatic spring cover (4) with a first fastening area on which the oneend of the pneumatic spring bellows (2) is secured by means of aclamping ring (6) or the like. A pneumatic spring piston (7) comprisinga face area (8) arranged opposite the pneumatic spring cover (4); asecond fastening area (9) on which the other end of the pneumatic springbellows (2) is secured by means of a clamping ring (10) or the like aswell; and a lateral roll-off surface (11) on which the pneumatic springbellows (2) is capable of rolling off, forming a loop (12); as well anexternal guide (13) for the spring bellows (2); characterized in thatthe external guide (13) consists of plastic with an embeddedreinforcement (14).
 2. The pneumatic spring system according to claim 1,characterized in that the plastic is a polymer with high impact strengthpreferably based on a polyamide or polyester.
 3. The pneumatic springsystem according to claim 1 or 2, characterized in that thereinforcement (14) consists of fibers.
 4. The pneumatic spring systemaccording to claim 3, characterized in that the reinforcement (14)consists of glass fibers.
 5. The pneumatic spring system according toany one of claims 1 to 4, characterized in that the reinforcement (14)is present in the form of a fabric (15, 16).
 6. The pneumatic springsystem according to claim 5, characterized in that the fabric is presentin the form of a warp-weft structure, whereby the warp direction (A) isthe axial direction and the weft direction (B) is the peripheraldirection of the external guide (13).
 7. The pneumatic spring systemaccording to claim 5, characterized in that the fabric is present in theform of a crossed structure.
 8. The pneumatic spring system according toclaims 5 to 7, characterized in that the fabric (15, 16) is arranged inone layer.